PE

CARTILAGE & LIGAMENTS

Cartilage has no blood supply but recieves nutrition through diffusion from the surrounding cappilary network.

White fibro-cartilage consists of tough tissue that acts as a shock absorber. It is found in parts of the body where there is a great amount of stress - for example, in the knee joint.

Cartilage does not heal very well once it is torn. This is mainly because it does not have a good blood supply.

Ligaments:

These join bone to bone.

They are bands of connective tissue that are very tough and resilient.

The ligaments prevent movements that are extreme and help to stop dislocation.

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PROBLEMS WITH JOINTS & HOW TO AVOID THEM

Arthiritis - inflammation of a joint.

Most people with arthiritis will experience pain and difficulty moving around.

You can take control of your symptoms by following a healthy lifestyle and thus continue to have a good quality of life.

Two of the most common forms of arthiritis are osteoarthiritis and rheumatoid arthirtis.

Osteoarthiritis is usually a result of ageing.

How to avoid joint problems:

Keeping to your ideal weight - eat a balanced healthy diet.

Don't do too much activity at one time - have rest intervals when appropriate.

Keep a good posture.

Wear shoes that have plenty of cushioning - especially when exercising.

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MOVEMENT

Flexion: a decrese in the angle around your joint - for example, bend your arm at the elbow and touch your shoulder with your hand.

Extension: when the angle of the bones that are moving is increased - for example, from a stooped or squat position you hen stand up. The angle between your femur and tibia increases, thus extension has taken place.

Abduction: movement of the body away from the midle of the body - for example, lying on your left side and lifting your right leg straight up away from the midline.

Adduction: opposite of abduction and is the movement towards the midline - for example, lowering your lifted leg that you have abducted towards the middle of your body.

Rotation: when the bone turns about its longitudinal axis within the joint - for example, a ballet dancer moves into first position and rotates the hip joint.

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EFFECTS OF LACTIC ACID

With the absence of oxygen lactic acid is formed in the working muscles.

Lactic acid causes muscle pain and often this leads us to stop or reduce the activity we are doing.

We cannot use the anaerobic system for long because of this build up of lactic acid.

When we recover, we take in oxygen and this helps to convert lactic acid into waste products.

An active healthy lifestyle will:

improve the muscles' capability of using oxygen more efficiently.

help muscles deal with larger amounts of lactic acid.

ensure that we can keep going for longer in activities and physical work.

help avoid illness and disease.

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TENDONS

Tendons attach muscles to bones

These are strong and can be a little flexible and they help to apply the power needed to move bones.

If contraction is excessively strong then tendons can be damaged. For example, the Achilles tendon is found in the lower leg and can be damaged.

Exercise without strain can strengthen tendons and make them more flexible and less prone to injury.

Tendonitis means inflammation of a tendon.

Symptoms are: tenderness; pain; swelling; movement being reduced in muscle/s that are pulled by inflamed tendon/s.

If you exercise excessively then some areas of the body are more prone to tendonitis - for example, tendons over the wrist and hand are the most commonly affected if you play a lot of squash.

How to avoid problems with tendons:

Avoid repetitive movements and overuse of the affected area.

Do exercises to strengthen the muscles around the affected tendon.

Seek medical advice if appropriate.

Rest the affected part.

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PAIRS OF MUSCLES

To produce movements, muscles either shorten, lengthen or they remain the same length when they contract.

Muscles work in pairs. As one muscle contracts, the other relaxes. Muscles that work together like this are called antagonistic pairs.

Examples of antagonistic pairs are: Biceps and triceps - at the arm joint. As the biceps bends the arms by contacting, the tricep relax. As the arm straightens, the opposite occurs.

Hamstrings and quadriceps - at the knee joint. The hamstrings contract and the quadriceps relax and the knee bends. As the knee straightens, the quads contract and the hamstrings relax.

Agonist - this is the muscle that produces the desired joint movement and is also known as the prime mover - for example, the biceps brachii is ths muscle that produces the flexion movement at the elbow.

Antagonist - for movement to be coordinated, muscles work in pairs so that control is maintaines. The movement caused by the agonist is countered by the acton of the opposing muscle called the antagonist - for example, the action at the elbow caused by the biceps shortening is opposed by the lengthening of the triceps, whichacts as the antagonist.

Synergists:These refer to muscles that are actively helping the prime mover or agonist to produce the desired movement.